AN 100: In-System Programmability Guidelines

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ID 683546
Date 9/22/2014
Public
Document Table of Contents
Document Table of Contents x
1. In-System Programmability Guidelines
1. In-System Programmability Guidelines x
1.1. General ISP Guideline 1.2. IEEE Std. 1149.1 Signals 1.3. Sequential versus Concurrent Programming 1.4. ISP Troubleshooting Guidelines 1.5. ISP through Embedded Processors 1.6. ISP through In-Circuit Testers 1.7. Document Revision History
1.1. General ISP Guideline x
1.1.1. Operating Conditions 1.1.2. User Flash Memory Operations During In-System Programming 1.1.3. Interrupting In-System Programming 1.1.4. MultiVolt Devices and Power-Up Sequences 1.1.5. I/O Pins Tri-Stated During In-System Programming 1.1.6. Pull-Up and Pull-Down of JTAG Pins During In-System Programming
1.1.1. Operating Conditions x
1.1.1.1. ISP Voltage 1.1.1.2. Input Voltages
1.2. IEEE Std. 1149.1 Signals x
1.2.1. TCK Signal 1.2.2. Programming Through a Download Cable 1.2.3. Disabling IEEE Std. 1149.1 Circuitry 1.2.4. Working with Different Voltage Levels
1.3. Sequential versus Concurrent Programming x
1.3.1. Sequential Programming 1.3.2. Concurrent Programming 1.3.3. Selecting Sequential or Concurrent Programming 1.3.4. Devices in Different Modes
1.4. ISP Troubleshooting Guidelines x
1.4.1. Invalid ID and Unrecognized Device Messages 1.4.2. Verify the JTAG Chain Continuity 1.4.3. Check the Voltage Levels of the Board During In-System Programming 1.4.4. Random Signals on JTAG Pins 1.4.5. Software Issues
1.5. ISP through Embedded Processors x
1.5.1. Processor and Memory Requirements 1.5.2. Porting the Jam Player
1. In-System Programmability Guidelines

1.2.4. Working with Different Voltage Levels

When devices in a JTAG chain operate at different voltage levels, an output voltage specification of a device must meet the input voltage specification of the subsequent device.

If the devices do not meet this criteria, you must add additional circuitry, such as a level-shifter, to adjust the voltage levels. For example, when a 5.0-V device drives a 2.5-V device, you must adjust the 5.0-V output voltage of the device to meet the 2.5-V input voltage specification of the subsequent device.

Because all devices in a JTAG chain are tied together, you must also ensure that the TDO output of the first device meets the TDI input voltage specification of the subsequent device to program a chain of devices successfully

All Altera ISP-capable devices include a MultiVolt I/O feature, which allows these devices to interface with systems that have different supply voltages. You can set all MultiVolt devices for 3.3-V, 2.5-V, 1.8-V, or 1.5-V I/O operation. The JTAG pins of MultiVolt devices support these voltage levels.

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